Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: CHAPTER III PHYSICAL EXERCISE AND LONGEVITY We have treated thus far what may be described as the historical aspect of our subject. Even more important is the question of the relation of exercise to the individual life. Life as commonly regarded is opposed to death, and the desire to prolong life is a natural and a commendable one. It is interesting, therefore, to inquire to what extent physical exercises and athletic sports contribute to this end, and what is the physiological process thereby involved. In order that we may understand what exercise does for the body, it will be necessary to know something of the body's structure and functions. According to modern physiology our material body is composed of innumerable atoms and cells, which have been built up into various tissues, bones, muscles, and organs. Many of these cells correspond to the lowest forms of animal life and have their period of birth, activity, and death, just as other living organisms do. In his simplest state a man may be regarded as a community of organismscapable of doing a certain amount of physiological work. This work consists in the maintenance of (1) animal heat, termed calorific work; (2) nervous or vital power, termed internal work; and (3) mechanical energy as muscular power, termed external work. Representing the standard of measurement by the force required to raise one pound one foot high, the amount of force expended daily by a man weighing one hundred and fifty pounds in the performance of these different kinds of work has been calculated to be about three thousand four hundred foot tons, ? that is, the amount of force necessary to raise three thousand four hundred tons one foot from the ground. This expenditure is divided as follows: Calorific work 2840 foot tons Inter...